SIV Vaccine Gives Hope for HIV Vaccine

Monkeys Vaccinated Against SIV Survive Longer After InfectionResults of two new studies sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), a component of the National Institutes of Health (NIH), suggest that even if an HIV vaccine offers imperfect protection against the virus, it might provide vaccinated individuals with an important benefit: a significant survival advantage after infection.

Such a survival advantage was observed in monkey studies conducted by two teams of researchers, one led by Norman L. Letvin, M.D., of Beth Israel Deaconess Medical Center, Harvard Medical School and the NIAID Vaccine Research Center (VRC), and the other by Mario Roederer, Ph.D., of the VRC. The researchers found that monkeys vaccinated against simian immunodeficiency virus (SIV) — a close relative of HIV that causes an AIDS-like disease in monkeys — and then exposed to the virus survived significantly longer than unvaccinated animals exposed to SIV.

Published in this week’s issue of Scienceand this month’s issue of the Journal of Experimental Medicine, the studies also identified a measurable marker of SIV vaccine effectiveness in monkeys — something known as an immune correlate of vaccine efficacy. Further study is needed to determine if the immune correlate could predict the effectiveness of a vaccine against HIV in humans.